Things You'll Need
Instructions
Travel to any Pokemon Center in "Pokemon HeartGold." Do the same with the other Nintendo DS and "Pokemon" game.
Talk to the trade attendant in the Pokemon Center, and place Magneton at the top of your party. Enter the trade station, and do the same with the other DS.
Trade Magneton to your other "Pokemon" game.
Travel to Mt. Coronet and level up Magneton by one level. It will then evolve into Magnezone.
Travel back to the Pokemon Center. Talk to the trade attendant, and trade Magnezone to "Pokemon HeartGold." You will now have Magnezone in your "Pokemon HeartGold" file.